U.S. Pat. No. 4,961,588 describes the prior art sealing means employed to provide a seal between a windbox and a rotating cylinderlot hopper of a rotary kiln. The 4,961,588 patent also discloses the use of a plurality of finger-like members to cooperatively yield a radial seal. As related in that patent such a plurality of fingers is said to provide a seal in instances wherein the cylinder is eccentric. In actual practice, while the sealing fingers are an improvement, they do not seal appropriately when an out of round cylinder is encountered. This is a significant problem in as much as out of round cylinders are the norm rather than the exception in as much as the heat and loading applied to the cylinders normally cause the overhung end of the cylinder to assume an eccentric shape relative to the axis of rotation of the cylinder. Applicant's business concerns maintenance and repair of such devices and considerable experimentation has been undertaken to restore an eccentric cylinder to a satisfactory sealing condition.
One prior attempt was to use a truing ring with a pseudo surface welded to the outer periphery thereof, the truing ring being concentric with the axis of rotation. This effort led to excessive cost due to the necessity of welding the pseudo-cylinder surface to the truing ring at the kiln site. Further thermal expansion of and contraction of the ring and pseudo cylinder surface resulted in failure of the welds. Accordingly, it is necessary to find a way to present the sealing fingers with a relatively uniform surface to minimize dynamic deflection of the fingers.